Anyone know what is a traumatic basilar artery aneurysm?

As the name suggests: It is aneurysm of dilatation of the basilar artery (at the back side of brain) due arterial wall disruption as a result of injury.

Trauma: Head or neck injury of significant force can damage the entire or partial arterial wall and cause a dilation as a full thickness aneurysmal wall or a partial injury with pseudoaneurysm- pulsatille hematoma. The two posterior neck arteries, the vertebral s join to form the basilar artery to the brain..